1 files changed, 322 insertions, 0 deletions
diff --git a/arch/c6x/kernel/signal.c b/arch/c6x/kernel/signal.c
new file mode 100644
index 000000000..862460c3b
--- /dev/null
+++ b/arch/c6x/kernel/signal.c
@@ -0,0 +1,322 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Port on Texas Instruments TMS320C6x architecture
+ *
+ *  Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
+ *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
+ *
+ *  Updated for 2.6.34: Mark Salter <msalter@redhat.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/uaccess.h>
+#include <linux/syscalls.h>
+#include <linux/tracehook.h>
+
+#include <asm/asm-offsets.h>
+#include <asm/ucontext.h>
+#include <asm/cacheflush.h>
+
+
+/*
+ * Do a signal return, undo the signal stack.
+ */
+
+#define RETCODE_SIZE (9 << 2)	/* 9 instructions = 36 bytes */
+
+struct rt_sigframe {
+	struct siginfo __user *pinfo;
+	void __user *puc;
+	struct siginfo info;
+	struct ucontext uc;
+	unsigned long retcode[RETCODE_SIZE >> 2];
+};
+
+static int restore_sigcontext(struct pt_regs *regs,
+			      struct sigcontext __user *sc)
+{
+	int err = 0;
+
+	/* The access_ok check was done by caller, so use __get_user here */
+#define COPY(x)  (err |= __get_user(regs->x, &sc->sc_##x))
+
+	COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
+	COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
+	COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
+
+	COPY(a16); COPY(a17); COPY(a18); COPY(a19);
+	COPY(a20); COPY(a21); COPY(a22); COPY(a23);
+	COPY(a24); COPY(a25); COPY(a26); COPY(a27);
+	COPY(a28); COPY(a29); COPY(a30); COPY(a31);
+	COPY(b16); COPY(b17); COPY(b18); COPY(b19);
+	COPY(b20); COPY(b21); COPY(b22); COPY(b23);
+	COPY(b24); COPY(b25); COPY(b26); COPY(b27);
+	COPY(b28); COPY(b29); COPY(b30); COPY(b31);
+
+	COPY(csr); COPY(pc);
+
+#undef COPY
+
+	return err;
+}
+
+asmlinkage int do_rt_sigreturn(struct pt_regs *regs)
+{
+	struct rt_sigframe __user *frame;
+	sigset_t set;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current->restart_block.fn = do_no_restart_syscall;
+
+	/*
+	 * Since we stacked the signal on a dword boundary,
+	 * 'sp' should be dword aligned here.  If it's
+	 * not, then the user is trying to mess with us.
+	 */
+	if (regs->sp & 7)
+		goto badframe;
+
+	frame = (struct rt_sigframe __user *) ((unsigned long) regs->sp + 8);
+
+	if (!access_ok(frame, sizeof(*frame)))
+		goto badframe;
+	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+		goto badframe;
+
+	set_current_blocked(&set);
+
+	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
+		goto badframe;
+
+	return regs->a4;
+
+badframe:
+	force_sig(SIGSEGV);
+	return 0;
+}
+
+static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
+			    unsigned long mask)
+{
+	int err = 0;
+
+	err |= __put_user(mask, &sc->sc_mask);
+
+	/* The access_ok check was done by caller, so use __put_user here */
+#define COPY(x) (err |= __put_user(regs->x, &sc->sc_##x))
+
+	COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
+	COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
+	COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
+
+	COPY(a16); COPY(a17); COPY(a18); COPY(a19);
+	COPY(a20); COPY(a21); COPY(a22); COPY(a23);
+	COPY(a24); COPY(a25); COPY(a26); COPY(a27);
+	COPY(a28); COPY(a29); COPY(a30); COPY(a31);
+	COPY(b16); COPY(b17); COPY(b18); COPY(b19);
+	COPY(b20); COPY(b21); COPY(b22); COPY(b23);
+	COPY(b24); COPY(b25); COPY(b26); COPY(b27);
+	COPY(b28); COPY(b29); COPY(b30); COPY(b31);
+
+	COPY(csr); COPY(pc);
+
+#undef COPY
+
+	return err;
+}
+
+static inline void __user *get_sigframe(struct ksignal *ksig,
+					struct pt_regs *regs,
+					unsigned long framesize)
+{
+	unsigned long sp = sigsp(regs->sp, ksig);
+
+	/*
+	 * No matter what happens, 'sp' must be dword
+	 * aligned. Otherwise, nasty things will happen
+	 */
+	return (void __user *)((sp - framesize) & ~7);
+}
+
+static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
+			  struct pt_regs *regs)
+{
+	struct rt_sigframe __user *frame;
+	unsigned long __user *retcode;
+	int err = 0;
+
+	frame = get_sigframe(ksig, regs, sizeof(*frame));
+
+	if (!access_ok(frame, sizeof(*frame)))
+		return -EFAULT;
+
+	err |= __put_user(&frame->info, &frame->pinfo);
+	err |= __put_user(&frame->uc, &frame->puc);
+	err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+
+	/* Clear all the bits of the ucontext we don't use.  */
+	err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
+
+	err |= setup_sigcontext(&frame->uc.uc_mcontext,	regs, set->sig[0]);
+	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+	/* Set up to return from userspace */
+	retcode = (unsigned long __user *) &frame->retcode;
+
+	/* The access_ok check was done above, so use __put_user here */
+#define COPY(x) (err |= __put_user(x, retcode++))
+
+	COPY(0x0000002AUL | (__NR_rt_sigreturn << 7));
+				/* MVK __NR_rt_sigreturn,B0 */
+	COPY(0x10000000UL);	/* SWE */
+	COPY(0x00006000UL);	/* NOP 4 */
+	COPY(0x00006000UL);	/* NOP 4 */
+	COPY(0x00006000UL);	/* NOP 4 */
+	COPY(0x00006000UL);	/* NOP 4 */
+	COPY(0x00006000UL);	/* NOP 4 */
+	COPY(0x00006000UL);	/* NOP 4 */
+	COPY(0x00006000UL);	/* NOP 4 */
+
+#undef COPY
+
+	if (err)
+		return -EFAULT;
+
+	flush_icache_range((unsigned long) &frame->retcode,
+			   (unsigned long) &frame->retcode + RETCODE_SIZE);
+
+	retcode = (unsigned long __user *) &frame->retcode;
+
+	/* Change user context to branch to signal handler */
+	regs->sp = (unsigned long) frame - 8;
+	regs->b3 = (unsigned long) retcode;
+	regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
+
+	/* Give the signal number to the handler */
+	regs->a4 = ksig->sig;
+
+	/*
+	 * For realtime signals we must also set the second and third
+	 * arguments for the signal handler.
+	 *   -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
+	 */
+	regs->b4 = (unsigned long)&frame->info;
+	regs->a6 = (unsigned long)&frame->uc;
+
+	return 0;
+}
+
+static inline void
+handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
+{
+	switch (regs->a4) {
+	case -ERESTARTNOHAND:
+		if (!has_handler)
+			goto do_restart;
+		regs->a4 = -EINTR;
+		break;
+
+	case -ERESTARTSYS:
+		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
+			regs->a4 = -EINTR;
+			break;
+		}
+		fallthrough;
+	case -ERESTARTNOINTR:
+do_restart:
+		regs->a4 = regs->orig_a4;
+		regs->pc -= 4;
+		break;
+	}
+}
+
+/*
+ * handle the actual delivery of a signal to userspace
+ */
+static void handle_signal(struct ksignal *ksig, struct pt_regs *regs,
+			  int syscall)
+{
+	int ret;
+
+	/* Are we from a system call? */
+	if (syscall) {
+		/* If so, check system call restarting.. */
+		switch (regs->a4) {
+		case -ERESTART_RESTARTBLOCK:
+		case -ERESTARTNOHAND:
+			regs->a4 = -EINTR;
+			break;
+
+		case -ERESTARTSYS:
+			if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
+				regs->a4 = -EINTR;
+				break;
+			}
+
+			fallthrough;
+		case -ERESTARTNOINTR:
+			regs->a4 = regs->orig_a4;
+			regs->pc -= 4;
+		}
+	}
+
+	/* Set up the stack frame */
+	ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
+	signal_setup_done(ret, ksig, 0);
+}
+
+/*
+ * handle a potential signal
+ */
+static void do_signal(struct pt_regs *regs, int syscall)
+{
+	struct ksignal ksig;
+
+	/* we want the common case to go fast, which is why we may in certain
+	 * cases get here from kernel mode */
+	if (!user_mode(regs))
+		return;
+
+	if (get_signal(&ksig)) {
+		handle_signal(&ksig, regs, syscall);
+		return;
+	}
+
+	/* did we come from a system call? */
+	if (syscall) {
+		/* restart the system call - no handlers present */
+		switch (regs->a4) {
+		case -ERESTARTNOHAND:
+		case -ERESTARTSYS:
+		case -ERESTARTNOINTR:
+			regs->a4 = regs->orig_a4;
+			regs->pc -= 4;
+			break;
+
+		case -ERESTART_RESTARTBLOCK:
+			regs->a4 = regs->orig_a4;
+			regs->b0 = __NR_restart_syscall;
+			regs->pc -= 4;
+			break;
+		}
+	}
+
+	/* if there's no signal to deliver, we just put the saved sigmask
+	 * back */
+	restore_saved_sigmask();
+}
+
+/*
+ * notification of userspace execution resumption
+ * - triggered by current->work.notify_resume
+ */
+asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,
+				 int syscall)
+{
+	/* deal with pending signal delivery */
+	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
+		do_signal(regs, syscall);
+
+	if (thread_info_flags & (1 << TIF_NOTIFY_RESUME))
+		tracehook_notify_resume(regs);
+}